Niall O'Brien's perfectly paced century enabled Leicestershire to beat Hampshire by six wickets in a rain-truncated match at the Ageas Bowl.

O'Brien hammered seven sixes, including the winning hit off James Tomlinson - which also brought up his century, as he reached 105 not out and Leicestershire chased down a revised target of 186 from 25 overs with four balls to spare.

Leicestershire, who were heavily beaten by Gloucestershire on Tuesday, required 10 from Tomlinson's last over but O'Brien made light of it by hitting the first ball for four and the second over the ropes at mid-wicket.

It gave the Foxes their their second win in four matches, while Hampshire slumped to their third defeat to make it difficult for them to qualify for the latter stages unless they have a huge upturn in form.

Hampshire won the toss, chose to bat first on a comfortable batting wicket and made a challenging 275 for nine, although they failed to make the best of a scintillating opening stand of 88 in 12.5 overs between Michael Carberry and James Adams.

At the close of the innings, Leicestershire would have been required to score at the rate of 5.5 an over but a deluge wiped three hours from the playing time and the target was revised to more than seven an over under the Duckworth-Lewis calculations.

In effect Leicestershire had half the overs in which to score about two-thirds of Hampshire's total, daunting enough at the best of times, but O'Brien was soon in his stride and the new total always looked to be in sight.

So it proved. Angus Robson (15) mistimed a pull off Tomlinson to Danny Briggs at mid-off at 28, but then came the highest stand of the match, 95 between O'Brien and Greg Smith for the second wicket in 12.1 overs.

Smith (34) went to a brilliant diving catch by Matt Coles at mid-on with Leicestershire needing 63 to win.

Hampshire hopes were raised briefly when Matthew Boyce and Dan Redfern fell in quick succession only for Tom Wells to keep O'Brien company as Leicestershire kept their nerve and their concentration.

O'Brien faced only 72 balls and had one escape when Tomlinson on the mid-wicket ropes failed to hold on, although he managed in the same action to avert another six to the Irishman.

Leicestershire went into the match without experienced Scott Styris and in the last over of the Hampshire innings, Shiv Thakor appeared to damage a hand fielding off his own bowling.

Hampshire, too, were weakened with James Vince away with England Lions and Glenn Maxwell and Kyle Abbott required for training camps by their countries.

Even without Vince, Hampshire raced away at the start through Carberry and Adams but then faltered after Adams had gone at 88 and Carberry at 95 for two after hitting three sixes and seven fours in his 50-ball 61.

In rapid succession, Hampshire lost Adam Wheater, Sean Ervine, Liam Dawson, Will Smith and Matt Coles so that six wickets had fallen for 83 in 22 overs.

Much of the credit for that must go the spinners, James Sykes, Redfern and Jigar Naik who between them bowled 29 overs and took six wickets while only conceding 130 when the pressure was on.

Hampshire were revived from 171 for seven by a stand of 70 in 10.1 overs between Sean Terry and Chris Wood for the eighth wicket. Terry made a competition-best 63 and even after he was ninth out at 246, there was last-wicket defiance from Danny Briggs and Tomlinson who put on an unbeaten 29.

But at the players came off for the change of innings, the rain came down and at one stage it looked as if play might have to be abandoned. O'Brien and Leicestershire will be glad that it was not.

O'Brien said: "I thought it was a fair score to chase, the equation was about right.

"We have done poorly in the County Championship and the Twenty20 with a young side so this has kept our season going. We have big matches coming up against Yorkshire and Northamptonshire.

"I got a ton here for Northants in 2011 and I felt I owed the side some runs . It helped that batting got better as the result of the rain.

"It was very important I was there at the end to get the lads home but the real man of the match was young James Sykes who took three very economical wickets."

Hampshire top scorer Terry said: "I set myself a target of batting through and did not quite happen. My aim was to keep the scoreboard ticking over with singles and getting the boundaries later.

"Sometimes I play some dumb cricket but not this time. The lads are downhearted because it is our third defeat in four and we have a lot of work to do now."